Organophosphonate-based PNA-functionalization of silicon nanowires for label-free DNA detection

Anna Cattani-Scholz, Daniel Pedone, Manish Dubey, Stefan Neppl, Bert Nickel, Peter Feulner, Jeffrey Schwartz, Gerhard Absteiter, Marc Tornow

Research output: Contribution to journalArticlepeer-review

97 Scopus citations


We investigated hydroxyalkylphosphonate monolayers as a novel platform for the biofunctionalization of silicon-based field effect sensor devices. This included a detailed study of the thin film properties of organophosphonate films on Si substrates using several surface analysis techniques, including AFM, ellipsometry, contact angle, X-ray photoelectron spectroscopy (XPS), X-ray reflectivity, and current-voltage characteristics in electrolyte solution. Our results indicate the formation of a dense monolayer on the native silicon oxide that has excellent passivation properties. The monolayer was biofunctionalized with 12 mer pepticle nucleic acid (PNA) receptor molecules in a two-step procedure using the heterobifunctional linker, 3-maleimidopropionic-acid- N-hydroxysuccinimidester. Successful surface modification with the probe PNA was verified by XPS and contact angle measurements, and hybridization with DNA was determined by fluorescence measurements. Finally, the PNA functionalization protocol was translated to 2 μm long, 100 nm wide Si nanowire field effect devices, which were successfully used for label-free DNA/PNA hybridization detection.

Original languageEnglish (US)
Pages (from-to)1653-1660
Number of pages8
JournalACS Nano
Issue number8
StatePublished - Aug 2008

All Science Journal Classification (ASJC) codes

  • General Engineering
  • General Materials Science
  • General Physics and Astronomy


  • Biosensor
  • DNA/PNA hybridization
  • Heterobifunctional linker
  • Organophosphonate monolayers
  • Silicon nanowire device
  • Surface characterization
  • X-ray reflectivity
  • XPS


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